An American ambassador and three of his diplomatic colleagues were killed Tuesday in an attack on the American consulate in Bengazi, Libya -- the first time an American diplomat has been killed in at least two decades. President Barack Obama has ordered increased security for U.S. diplomatic posts abroad.

An American ambassador and three of his diplomatic colleagues were killed Tuesday in an attack on the American consulate in Bengazi, Libya -- the first time an American diplomat has been killed in at least two decades. President Barack Obama has ordered increased security for U.S. diplomatic posts abroad.